handle throughabouts -- do not announce going through

CHANGELOG.md

@@ -14,6 +14,7 @@
       - Pass functions instead of strings to `WayHandlers.run()`, so it's possible to mix in your own functions.
       - Reorders arguments to `WayHandlers` functions to match `process_way()`.
       - Profiles must return a hash of profile functions. This makes it easier for profiles to include each other.
+      - Guidance: add support for throughabouts
 
 # 5.9.2
     - API:

features/guidance/roundabout-turn.feature

@@ -567,5 +567,5 @@ Feature: Basic Roundabout
             | ab    | residential   | in      |            |        |
 
         When I route I should get
-            | waypoints | turns                                                    | route                      |
+            | waypoints | turns                    | route              |
-            | a,f       | depart,turn right,roundabout turn straight exit-1,arrive | in,through,through,through |
+            | a,f       | depart,turn right,arrive | in,through,through |

features/guidance/roundabout.feature

@@ -763,7 +763,7 @@ Feature: Basic Roundabout
 
         When I route I should get
            | waypoints | bearings | route       | turns                           |
-           | e,f       | 90 90    | edf,edf,edf | depart,roundabout-exit-1,arrive |
+           | e,f       | 90 90    | edf,edf     | depart,arrive                   |
            | e,h       | 90 135   | edf,gch,gch | depart,roundabout-exit-2,arrive |
            | g,f       | 45 90    | gch,edf,edf | depart,roundabout-exit-2,arrive |
            | g,h       | 45 135   | gch,gch,gch | depart,roundabout-exit-1,arrive |
@@ -843,6 +843,6 @@ Feature: Basic Roundabout
 
 
         When I route I should get
-            | from | to | route                        | turns                                                             | distance |
+            | from | to | route                | turns                                 | distance |
-            | e    | k  | ebds,ebds,ds,ufghl,jhik,jhik | depart,rotary-exit-1,rotary-exit-1,rstur-exit-2,turn right,arrive | 189.1m   |
+            | e    | k  | ebds,ufghl,jhik,jhik | depart,rstur-exit-2,turn right,arrive | 189.1m   |
-            | 1    | k  | ebds,ds,ufghl,jhik,jhik      | depart,rotary-exit-1,rstur-exit-2,turn right,arrive               | 159.1m   |
+            | 1    | k  | ebds,ufghl,jhik,jhik | depart,rstur-exit-2,turn right,arrive | 159.1m   |

src/extractor/guidance/roundabout_handler.cpp

@@ -504,15 +504,23 @@ Intersection RoundaboutHandler::handleRoundabouts(const RoundaboutType roundabou
     }
     else
     {
+        bool crossing_roundabout = false;
         for (std::size_t cnt = 0, idx = lhs ? intersection.size() - 1 : 0;
              cnt < intersection.size();
              ++cnt, idx += step)
         {
-            auto &road = intersection[idx];
+            auto &turn = intersection[idx];
-            if (!road.entry_allowed)
-                continue;
-            auto &turn = road;
             const auto &out_data = node_based_graph.GetEdgeData(turn.eid);
+
+            // A roundabout consists of exactly two roads at an intersection. by toggeling this
+            // flag, we can switch between roads crossing the roundabout and roads that are on the
+            // same side as via_eid.
+            if (out_data.roundabout || out_data.circular)
+                crossing_roundabout = !crossing_roundabout;
+
+            if (!turn.entry_allowed)
+                continue;
+
             if (out_data.roundabout || out_data.circular)
             {
                 if (can_exit_roundabout_separately)
@@ -524,8 +532,21 @@ Intersection RoundaboutHandler::handleRoundabouts(const RoundaboutType roundabou
             }
             else
             {
-                turn.instruction = TurnInstruction::ENTER_AND_EXIT_ROUNDABOUT(
+                // Distinguish between throughabouts and entering a roundabout to directly exit: In
-                    roundabout_type, getTurnDirection(turn.angle));
+                // case of a throughabout, both enter and exit do not show roundabout tags (as we
+                // already have checked, when arriving here) and the enter/exit are nearly straight
+                // and on different sides of the roundabouts
+                if (util::angularDeviation(turn.angle, STRAIGHT_ANGLE) < FUZZY_ANGLE_DIFFERENCE &&
+                    crossing_roundabout)
+                {
+                    turn.instruction = getInstructionForObvious(
+                        intersection.size(), via_eid, isThroughStreet(idx, intersection), turn);
+                }
+                else
+                {
+                    turn.instruction = TurnInstruction::ENTER_AND_EXIT_ROUNDABOUT(
+                        roundabout_type, getTurnDirection(turn.angle));
+                }
             }
         }
     }